The purpose of this study was to evaluate the safety and military effectiveness of wearing contact lenses in an operational armor environment. Male volunteers from eight battalions of an armored division at Fort Hood were extended-wear soft contact lenses SCLs or spectacles for up to six months. During this period, physiological and subjective measures were obtained, along with logistical and personnel support information. Three types of SCLs were worn high, medium and low water content lenses. Subjects followed their normal training schedule in garrison and on training ranges. Seventy-four percent of those successfully fitted with SCLs wore their lenses for the duration of the study, when administrative losses were factored out. More than a third of the SCL wearers experienced one or more ocular conditions requiring at least a temporary suspension of lens wear. A large majority of contact lens wearers indicated that SCLs improved their vision and job performance. These results represent the beginning of a database intended to address a variety of operational settings, environmental factors and job demands.